Portable structures, such as tents, have been widely known and used for centuries. Unfortunately, such structures suffer from common problems that have also been widely known, with various solutions proposed through the years. A particular problem has involved the erecting, disassembly, and packing of such structures. For example, many tents include a plurality of separate parts, such as multiple poles and attaching members and require considerable effort to assemble and disassemble. Several of such tents require two or more persons to manipulate the tent and frame so that it can be readily erected. Further, these tents may be difficult or cumbersome to store and to transport. These problems are particularly disadvantageous for tents that are to be used during backpacking by one or two people. Under these circumstances, a light, easily erected and compacted tent structure is most desirable.
Solutions to these problems have been proposed through the years. Single piece tent structures that are compactable and easy to erect have been disclosed in U.S. Pat. No. 3,675,667 to Miller, U.S. Pat. Nos. 3,960,161, 3,990,463 and 4,825,892, each to Norman, U.S. Pat. No. 4,858,634 to McLeese, U.S. Pat. No. 5,163,461 to Invanovich et al. and U.S. Pat. No. 5,249,592 to Springer. The structures disclosed in these patents generally include a fabric shell forming the various outer surfaces of the erected structure, and a frame for supporting the shell. The frame is generally a single loop of flexible, coilable, resilient material secured along its length to the structure's fabric.
The tent structures disclosed in these patents, however, have not satisfactorily solved the existing problems. The tent of U.S. Pat. No. 3,960,161 to Norman, for instance, is generally wider about its upper portion than about its base portion, and is thus top heavy and tends to be unstable. To stabilize this tent of the prior art, tent end walls extend outward from the frame ends with ties for attaching to stakes in the ground. Such a configuration leads to difficulty in erecting as the structure will tend to sway or rock away from a level position.
Also, because ties and ground stakes are required to strain side walls to hold the tent structure in the desired upright position, stress is present in the ties, ground stakes, and side walls. This stress can lead to undesirable tearing of the body near the ties, untying during use, and dislodgment of ground stakes. This may also lead to a difficulty in using such a tent structure in areas where ground stakes are not practical, including hard surfaces such as concrete, rock, wood decking, wood flooring or on very soft surfaces such as in sand or very loose turf.
Also, these tent structures of the prior art require end panels that extend outward at an angle relative to the vertical so as to stabilize the top heavy structure. Outwardly extending end panels, however, are disadvantageous due to the inclination allowing for more direct rain or snow impact and accumulation. It is preferable to have end panels which extend generally in the vertical so as to better avoid direct impact of rain and snow.
An additional disadvantageous limitation of many prior art structures is the requirement of a floor. The tents structures of the prior art generally requires a floor so as to obtain the overall shape of the tent structure. But even with a floor, such tent structures of the prior art create stress on the frame to hold it in desired place. The stress in the floor resulting from holding the frame in place can lead to shear tearing and other premature floor failure.
Moreover, it is often desired that the tent structure be configured for use without a floor so as to apply to a larger range of applications, such as covering a pool, ground foliage, ground workspace or vehicles. Although the prior art does include descriptions of such tents without a floor, such embodiments generally have a "potato chip" shape. These structures, while generally useful for applications such as free standing coverings for a pool, foliage, vehicle or groundwork, also require tie-downs, vertical poles, struts and other additional supports or anchors to render such structures stable.
Also, given that such tents may be sized for one or more persons, as well as other various applications, a large entry passage panel may be desired for entering and exiting the tent. The structures taught by such tents in the prior art, however, inherently limit the entry passage to a relatively narrow, small panel at the end of the tent. Thus, entry and exit of this tent is made more difficult.
For the foregoing reasons, an unresolved need exists for an improved portable structure.